DESCRIPTION (Applicant's abstract): The proposed research seeks to apply decision analytic techniques in order to evaluate recently developed, minimally invasive techniques for percutaneous, in-situ tumor ablation in patients with liver metastases from colorectal carcinoma (CRC). It is now well documented that long term survival can be improved in patients with limited hepatic metastases by operative metastasectomy. However, the impact of in-situ ablative techniques on long-term survival is unknown. In addition, the importance of diagnostic imaging in selecting candidates for therapy, specifically the impact of diagnostic accuracy on treatment outcomes, has received relatively little attention. None of these techniques have been formally evaluated in order to determine their relative cost effectiveness. We have recently developed a Markov decision model based on the costs, performance characteristics, and outcomes of various diagnostic tests and surgical treatment strategies, in order to evaluate the cost effectiveness of operative metastasectomy in patients with CRC liver metastases. In the proposed research, we will further develop, verify, and refine this model in order to perform cost effectiveness analysis of strategies for diagnostic imaging and in-situ ablation in patients with CRC liver metastases. We will also explore the possibility that in-situ ablation, given its generally lower cost, morbidity, and mortality, could provide relatively cost effective life extension for patients in whom cure is impossible. Finally, we will investigate the effect of different analytic perspectives on health outcomes and costs at the population level. The research is multidisciplinary in nature, and represents a collaborative effort between researchers in the fields of health economics, health services research, and clinical cancer care. It will add to our knowledge base concerning the economic aspects of cancer management, and will provide guidance in the appropriate use of diagnostic and therapeutic interventions in patients with hepatic metastases. The research may also identify areas for potential clinical trials providing direct comparisons of surgical and percutaneous techniques, and/or evaluations of strategies for diagnostic liver imaging.